Got a few questions that I can't see answered elsewhere or in the readme file:

What is the path for script - should it be the full file name or the directory, eg ending ...cgi-bin/subscriber.cgi ? or just .../cgi-bin/

Any tips about what sort of things can go in the header and footer variables? Eg. Can I add text in here about going to the website to download an html version of an email in the header, or put how to unsubscribe in the footer so it's there on every email?

If I want to change anything later should I reload firstrun.cgi and reset the variables?

If I want to set up a second newsletter on the same site, can I put the files in another directory and they wil act independently?

The header and footer only affect the displayed pages that the users and administrators see. They do not affect any email that is sent out. The content of these variables can be any HTML really, as they are just what's added above and below everything on the pages.

If you need to change anything later, you do not need to use firstrun.cgi In fact, you shouldn't, because it resets everything. Instead, there is an "Edit Variables" screen in the admin panel.

If you set up another separate script in another directory, then it is independent.